JPS6058329B2 - How to install a bottom-mounted offshore structure using a used tanker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a bottom-mounted marine structure using a used tanker.

When constructing a bottom-mounted marine structure such as a breakwater using a used tanker, a mound is set up on the seabed using rubble, etc., the tanker is floated on the sea surface and towed above the mound, and then water is poured inside. Then, instead of water, the tanker is filled with solid heavy objects such as concrete or earth and sand, and installed on the mound.The frictional force between the tanker and the mound prevents it from moving horizontally due to waves, etc. are doing.

In order to increase the frictional force between the tanker and the mound to reliably prevent horizontal movement of the tanker, it is necessary to increase the coefficient of friction between them, or to increase the friction between the tanker and the solid heavy objects packed inside it. It is necessary to increase the total weight of However, in the case of tankers, the hull is made of steel, so the coefficient of friction between the tanker and the mound is smaller than that of a concrete caisson, and in order to obtain the same frictional force as a concrete caisson, it is necessary to It is necessary to increase the total weight by about 50% compared to the case of a concrete caisson, which is uneconomical. This invention was made in view of the above-mentioned circumstances, and it increases the resistance to waves etc. without increasing the total weight of the used tanker and solid heavy objects, thereby increasing the horizontal direction of the used tanker. The purpose of the present invention is to provide a method for installing a bottom-mounted marine structure using a used tanker that can reliably prevent movement.

In the method according to this invention, when installing a Nakayoshi tanker as a bottom-mounted marine structure by sinking it on a mound on the seabed, the hull of the used tanker is divided longitudinally into a plurality of compartments, and the above-mentioned In the compartment, the bottom skin plate between the left and right vertical bulkheads and the aggregate attached to this skin plate are separated from the ship's hull, and then the parts that were separated from the hull are lifted and reattached to the vertical bulkheads, so that the center part of the ship's bottom in the left-right direction is While forming a recess, in some other compartments,
The bottom shell plating outside the left and right vertical bulkheads, the lower part of the side shell plating, and the aggregate attached to these shell platings were cut off from the hull, the lower part of the remaining side shell plating was cut and removed, and then the parts that had been cut off from the hull first were removed. By lifting it up and reattaching it to the longitudinal bulkhead and the ship's side shell, a convex part is formed in the center of the ship's bottom in the left-right direction.This makes the bottom of the ship uneven when viewed from both the vertical and horizontal directions. The used tanker is placed on the mount so that the unevenness of the ship's bottom and the corresponding unevenness of the mount fit together. It is characterized by filling sand etc. between the bottom of the ship and the mount.

According to this invention, the irregularities on the bottom of the ship and the corresponding irregularities on the mount are fitted together, and sand or the like is filled between the hull and the mount at these fitting parts, so that the tanker and the solids packed inside it are Even if the total weight of the tanker is not particularly large, the resistance against waves and the like is increased, and horizontal movement of the tanker can be reliably prevented.

Furthermore, since the bottom of the ship is uneven when viewed from either the longitudinal or lateral direction, it is possible to reliably prevent the tanker from moving in both the longitudinal direction (lengthwise direction) and the lateral direction (widthwise direction). Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in Fig. 1, a used tanker 1 to be used as a bottom-mounted offshore structure is pulled into a dock 2.
As shown in FIGS. 2 to 5, the bottom of the ship is modified so that it has unevenness when viewed from both the vertical and horizontal directions.

In other words, first, in the evening. The hull of one anchor 1 is divided into a plurality of sections in the longitudinal direction with the transverse bulkhead 3 as a boundary. And 1
In some sections of the hull, both left and right ends of the bottom shell plate 5 between the left and right vertical bulkheads 4 and the aggregate 6 including large bones and small bones attached to this shell plate 5 were cut off from the hull. Let go. Next, the part separated from the hull is lifted up with a jack (not shown) and welded to the vertical bulkhead 4 again as shown in Figure 4, thereby creating a recess in the center of the ship's bottom in the left and right direction. form 7. In addition, the center tank 8 of tanker 1
A plurality of vertical pipes 10 extending from the upper deck 9 immediately inside the longitudinal bulkhead 4 to the recess 7 are appropriately arranged inside. Along with this,
In some other sections sandwiched in the recess 7, the bottom skin 5 and the side skin 11 outside the left and right vertical bulkheads 4
Both ends of the aggregate 6 including the large bones and small bones attached to the lower part and these outer plates 5 and 11 are cut and separated from the hull. Then, after cutting and removing the lower part of the remaining ship side shell plating 11,
The part that was previously separated from the hull is lifted up with a jack, and as shown in Figure 5, it is welded again to the vertical bulkhead 4 and the side shell plating 11, thereby attaching it to the center of the bottom of the ship in the left and right direction. A convex portion 12 is formed. In addition, a plurality of vertical pipes 10 extending from the upper deck 9 immediately outside the vertical bulkhead 4 to the bottom shell 5 are appropriately arranged in the side tank 13 of the tanker 1. on the other hand,
Mounted by rubble on the seabed at the location where the used tanker is installed 1
4, and its upper surface is formed with unevenness corresponding to the unevenness of the bottom of the ship.

Then, the tanker 1 modified as described above is pulled out to sea and towed above the mount 14, and then water is poured into the tanker 1 so that the unevenness on the bottom of the ship and the corresponding unevenness on the mount fit together. onto mount 14. Next, solid heavy objects such as earth and sand are charged and packed inside the hull, and the tanker 1 is installed at a predetermined position on the mount 14. Finally, as shown in FIG. 6 and FIG. Sand 17 or the like is filled through the pipe 10 between the fitting mount 14 and the circumferential wall of the recess 16, and the installation of the tanker 1 is completed. The arrangement of the unevenness on the bottom of the ship can be arbitrary. For example, as shown in FIG. In the other group, a convex portion 12 similar to that described above may be formed on the bottom of the ship.

In this way, the shape of the top surface of the mount corresponding to this becomes simple.

[Brief explanation of the drawing]

FIGS. 1 to 7 show an embodiment of the present invention in the order of steps,
Figure 1 is a cross-sectional view showing a used tanker before modification at the dock, Figure 2 is a longitudinal cross-sectional view showing the used tanker after modification at the dock, Figure 3 is a view taken along the line ■-■ in Figure 2, 4 and 5 are cross-sectional views taken along line ■-■ and line V-■ in FIG. 8th
The figure is a drawing corresponding to FIG. 3 showing another embodiment of the present invention. 1...Used tanker, 2...Dock,
4... Vertical bulkhead, 5... Bottom shell plate, 6...
... Aggregate, 7... Ship bottom recess, 11...
...Ship side outer plate, 12...Bottom protrusion, 14...
...Mount, 15...Mount convex part, 16.
...Mount recess, 17...Sand.

Claims (1)

[Claims] 1. When installing a used tanker as a submerged offshore structure on a mound on the seabed, the hull of the used tanker is divided into multiple sections in the longitudinal direction, and the left and right sections are placed in the dock in advance. After separating the bottom shell plate between the longitudinal bulkheads and the aggregate attached to this shell plate from the ship's hull, the parts separated from the hull are lifted and reattached to the longitudinal bulkhead, thereby forming a recess in the center of the ship's bottom in the left-right direction. In several other sections, the bottom skin outside the left and right vertical bulkheads, the lower part of the side skin, and the aggregate attached to these skins were separated from the hull, and the lower part of the remaining side skin was cut and removed. By lifting the part that was previously separated from the hull and reattaching it to the vertical bulkhead and the ship's side skin, a convex part is formed in the center of the ship's bottom in the left-right direction, thereby making the bottom uneven when viewed from both the vertical and horizontal directions. The top surface of the mound on the seabed is made to have an uneven surface that corresponds to the unevenness of the ship's bottom.
The used tanker is sunk onto a mound so that the unevenness of the ship's bottom and the corresponding unevenness of the mound fit together, and sand or the like is filled between the hull and the mound at these fitting parts. How to install a bottom-mounted offshore structure using a used tanker.